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Question

我试图在 php 中做 upvote/downvote 系统。我想投票给唯一一张已投票的图片，但不幸的是，在我的数据库中，所有图片都在增加到一张。

$con = mysqli_connect("localhost","root","","thesisdb");
if($upvote != "")  {

        /*im trying to do here , each of my image has vote/downvote button. but every image is increasing by one even you only vote for the selected image*/

    $vote_upvote = "update product set vote=vote+1 WHERE ID = '".$upvote."'  "; 
    $run_upvote = mysqli_query($con, $vote_upvote);

    if($run_upvote){

    echo "<h2 align='center'>You Upvoted It!</h2>"; 




}
    }


        /*same with downvote, all image increasing by one even you only click for one.*/
if($downvote != "")  {

    $vote_downvote = "update product set notvote= notvote+1  WHERE ID = '".$downvote."'";

    $run_downvote = mysqli_query($con, $vote_downvote);

    if($run_downvote){
    echo "<h2 align='center'>You downvoted It!</h2>"; 

}
}

/我的显示图片更具体/

    $result = mysql_query("SELECT * FROM product");

          echo "<table border='0'>
    <tr>
    <th>Product Name</th>
    <th>Product Price</th>
    <th>Product Type</th>
    <th>Image</th>


    </tr>";
    $sw = 0;


    while($row = mysql_fetch_array($result))
                           {
                          if($sw == 0) 
                            {
                                $mycolor = "#fff";
                                $sw = 1;
                            }
                        else
                            {
                                $mycolor = "#fff";
                                $sw = 0;
                            }
      echo "<tr bgcolor='".$mycolor."'>";

      echo "<td>" . $row['ProductName'] . "</td>";
      echo "<td>" . $row['ProductPrice'] . "</td>";
      echo "<td>" . $row['ProductType'] . "</td>";

     ?>

/* 我在这里做了一个两个按钮来支持/downvote*/

    <td><a name="upvote" href="customerview.php?upvote=<?=$row['ID']?>"><input type="submit" name="upvote" value="Upvote"/>  </a> </td>

<td><a href="customerview.php?downvote=<?=$row['ID']?>"><input type="submit" name="downvote" value="Downvote"/>  </a> </td>



     <?php
      echo "</tr>";
      }
    echo "</table>";




     ?>

Answer 1

if($upvote != "")  { //i dont know where you get this value from 

将此行改为

if(isset($_GET['upvote'])&&$_GET['upvote']!=""){
    $upvote=$_GET['upvote'];
        //your code to update upvote
        }
       if(isset($_GET['downvote'])&&$_GET['downvote']!=""){
$downvote=$_GET['downvote];
        //here is your code to update downvote
        }